Furnace



A 1,642,019 Sept. 139 L W. FOLTZ FURNACE Filed 001;. 27, 1920 iwfw Patented Sept, 13, 1927.

i iras-raras PATENT ortica- 'FURNA'CE.

-Applcatonlcd October 27, 1920. Serial No. 419,879.

laashpitgdoor:.or-someotherair inlet located in f f i-he-:gashpit i and intended' for regulating jthe :d-raftfthrough the fuel.

The draw-ing is diagrammatic, illustrating theA air heating appliance partlyin section, 90 Ain fconnectionwith .-a vfurnace of known-construction and= shown i'partly broken away.

Vln its essential elements, .the `invention comp-rises an fair `drum surrounding the out- -fletv iue o'fthe furnaceand lhaving.. a supply -conduit connecting it `with theiashpit of the "furnace, 'while-thecdelivery conduitfof the fair heating drum enters. the topof the furnace" through the breeching or. inner end `of the outlet yflue-andterm-inates ,ina plurality of branch conduits having'outletsnear or slightly `above 'Y the approximate fuel y.level intended tobev maintained in the furnace. .The advantage 'believed to accrueffrom this arrangementofair heating appliance is that 35 the regulation of thewa'irsupply to-theash- I .pit serveslzikewis'e` to regulate the flowof air'V through the air heating appliance, air-.flowing through said appliance in proportion to the resistance iti-encounters therein, and the resistance encountered by the air which flows upwardly through the grate and fuel, both supplies of air being subject to the draft developed in thevoutlet flue or chimney. A further merit of the construction is believed 47 to exist in an arrangement of air heating appliance for the secondaryl supply of air which utilizes some of the excess heat of the products of combustion which is not required for maintaining the necessary draft through the furnace. Due to not being located ywithin the furnace proper, this air heating appliance does not chill the re and thereby unnecessarily lower the possible efliciency of the furnace.

The drawin shows a cylindrical double box 2 separated from an ashpitby a grate .4.r A, firing door, ashpit door'- and clean-out door are respectively indicatedvat 5', Gand 7. The flap 8 of the ashpit` door isfadju'sftable onits pivot 9 as usualffor regulating the size of the air inlet tothe'ashpit. Aldiaphragm motor l0, subject tothe pressuredeveloped inthe boiler, is arranged in a. customary way for automatically raising and lowering the flap 8` through, the vconnecting link 11.

The outletflue `12 for :the products of com-` bustion, has an inlet'13 within-t-hefi'ipper Aend of the furnace. An air heating drum 14 surrounds the outletrflue 12 KVandj'is lconnected by a conduit 15 with the ashpit. The outlet or Y deliveryconduit 16 'for the air heating drum connects the drum 14 with the fire-'box portion vof theV furnaceby passing downwardly through the'centerfof the entrance 18 of theoutlet flue. vt its lower end, it preferably terminates in-aplurality of branch Kpassages which serve to deliverthe heatedair above the fuel bed -near the walls of the furnace in order not-to interfere with the firingoperation ,and likewise to induce the most intense combustion along 'the' heating surfaces of the furnace.

Inv the operation fof ythe furnace,v the flap 8 of thev ashpit door is'automaticallyv raised and lowered by the motor- 10 to controlfthe rate of combustion and thereby maintain ysome desired pressure inthe` boiler. The

air which enters the ashpithas two ,"paths lWhich it maytravel; one upwardly` through the grate. and the fuel and `out through the inlet 13 .of the .outlet liuc, ,and4 the other path= l.is throughfthe? conduit 15.air heating `drum vlll; and conduit 16 throughthe branch passages of which the air must travel before it is free to rise in the {ire-box, and move out through the inlet 13 of the outlet flue.

It is well understood in this art that the fuel is most economically burned if a proper secondary supply of heated air is caused to combine with the gases at such rate that the furnace, as a gas consumer, will equal itself as a gas producer. The ladvantage of preheating the air, is the saving of gas which might otherwise be chilled to below the ignition point by the secondary supply of air.

Much o f the benefits of preheating the air is lost if the heat for such preheating taken directly from the furnace. ccord 'wall beller i 'ivdecl into two parts; a are lngly, the air heating device if the Cri invention is located beyond the il`urnace proper in position to extract part of the heat from the outlet tine iter the products et conlbustion, which products are Vfrequently of a higher temperature than that which is necessary to maintain the desired draft in the chimney. t

Although but one specilic embodiment of this invention has heen herein shown and described, it will be understood that numerous details of the Construction shown may be altered or omitted without departing from the spirit ot' this invention as defined by the following' claims.

I claim l. rlfhe combination with a iturnace structure providing` a lirehox, an ashpit having; an air inlet and an outlet. a girate, an outlet Hue exterior to said furnace tor carrying therefrom the products of combustion, of an air heatingT drum surrounding` said outlet tine exterior to said furnace, an air supply conduit connecting: said air heating: drum with the said air outlet in said ashpit for conveying` air from said ashpit to said air heating drum. and an air delivery conduit for conveyingl air from said air healing drinn to said lire-hex, which said air supply conduit together with said air heating` drum and said air delivery conduit term one continuous air conduit exterior to said furnace han ing an inlet in the ashpit and haringr an outlet in the tire-box.

2. The combination with a furnace structure providing! a tire-box. an ashpit havingr an air inlet and an outlet. a grate, an outlet flue exterior to said furnace for carryingr therefrom the products et combustion, of an air heating drum surroundingf said outlet flue exterior to said furnace an air supply conduit connecting; said air heating drum with the said air outlet in said ashpit for conveying' air from said ashpit to said air heating drum` and an air delivery conduit for conveying air from said air heating drum to said lire-hex. which said air supply conduit together with said air heating drum and said air delivery conduit 'torni one eon tinuous air conduit exterior to said furnace having an inlet located below the grate and havingr an outlet located above the errate.

3. The combination with a furnace structure providing' a lire-box, an ashpit having' an air inlet and an outlet, a amate` an outlet tine exterior to said 'furnace `lier carrying therefrom the products ol' combustion, of an air heating drum surrounding said outlet tlue exterior to said furnace, an air supply conduit connecting said air heating drum with said air outlet in said ashpit for conveying air from said ashpit to said air heating` drum, and an air delivery conduit for conveyingair from said air heat ing drinn to said lire-box, said air delivery conduit terminating in a plurality of hraneh passages liaving outlets near the surroundingr wall ot the lire-hex but spaced a distance above the grate. which said air supply eon duit together with said ai r heating drum and said air delivery cond uit 'form one con tinuous air conduit exterior to said turnail'e having an inlet located below the grate and having an outlet located above the grate.

Il'. ('ontrolled means to supply air to the ash pit ol a lire hex, means to control the fion' ot air vtrom said ash pit and to direct a portion thereo't to a heating;r device posin tioned outside the lire boxv and itsl combustion chamber. in combination with means to direct air from said heating device to said lire box and discharge the saine above the bed of fuel on the grate thereof`r said means to control said flow from said aah pit arranged to automatically direct a quantity et air thereflroin correspondinawith the varying;V resistance lo the llow ot air through the fuel on said ,ejratm and .said means to direct the tlow ot air from said heating device arranged to automatically iflischargre the air flowing therethrough.

Signed at Chicago this 2.5 day et Oct., 1920.

IRA lV. FOLTZ. 

